Interfacial synthesis of luminescent 7 kDa silver clusters

Abstract

We report the synthesis of luminescent Ag clusters through the interfacial etching of mercaptosuccinic acid (MSA) protected silver nanoparticles, Ag@MSA, with guanine at the water-toluene interface. The clusters exhibiting well-defined absorption emit in the near-infrared (NIR) region. Crude clusters were separated using polyacrylamide gel electrophoresis (PAGE). The cluster solid, prepared by freeze drying, is highly hygroscopic. Biomolecular markers were used to identify the approximate mass of the cluster which was found to be 7 kDa, as mass spectrometry did not reveal specific signatures. The clusters were investigated using UV-Vis spectroscopy, transmission electron microscopy (TEM), energy dispersive analysis of X-rays (EDAX), X-ray photoelectron spectroscopy (XPS), infrared spectroscopy (IR), and fluorescence spectroscopy. Elemental analysis and IR studies reveal the protection of the cluster by two types of ligands, namely MSA and guanine. Fluorescence of the cluster is highly temperature dependent, with an increase in intensity with decrease in temperature. Influence of different ratios of reactants, etching capacity of different nucleobases and effect of temperature on the synthesis as well as possible single-phase etching were investigated. Sensitivity of the cluster to certain metal ions has been monitored using fluorescence spectroscopy.

Supported quantum clusters of silver as enhanced catalysts for reduction

“…Laser irradiation at 337 nm cleaves AgS-C, bond and Ag n S m clusters alone are observed in the gas phase. The intact chemical composition of the QC was not observed, as typical of the spectra of thiolated clusters [34,38]. Ag n S m - species observed in the gas phase are dissociation products as well as gas phase reaction products.…”

Uptake of Toxic Metal Ions from Water by Naked and Monolayer Protected Silver Nanoparticles: An X-ray Photoelectron Spectroscopic Investigation

“…Ag@MSA nanoparticles were prepared as per the published literature. 16 About 448.9 mg of MSA was dissolved in 100 mL of methanol with stirring, under ice-cold conditions. To this, AgNO 3 solution (85 mg of AgNO 3 in 1.7 mL of distilled water) was added.…”

Fluorescent Au(i)@Ag2/Ag3giant cluster for selective sensing of mercury(ii) ion

“…7,8 In spite of poor photostability towards oxidation, many reports are found showing a stronger fluorescence signal of silver clusters compared to gold confined in the same matrix. [10][11][12][13][14][15][16][17][18][19][20][21][22] Polyelectrolytes such as poly(amidoamine) dendrimer, poly(methacrylic acid), and poly(acrylic acid) have been widely employed for obtaining fluorescent Ag clusters in aqueous medium. [10][11][12][13][14][15][16][17][18][19][20][21][22] Polyelectrolytes such as poly(amidoamine) dendrimer, poly(methacrylic acid), and poly(acrylic acid) have been widely employed for obtaining fluorescent Ag clusters in aqueous medium.…”